JP2000290644A - Material for light-emitting device, and light-emitting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material, shown by a specific formula, efficiently emitting light of high brightness at a low voltage, excellent in stability in repeated service, capable of emitting light from a uniform plane, and useful for light-emitting devices or the like. SOLUTION: This compound is shown by formula I [R1 to R8 and R11 are each H or a substituent; X is O, S, N-R (R is H, an aliphatic hydrocarbon, aryl or the like); Z is N-Ra-Rb (Ra and Rb are each H, an aliphatic hydrocarbon, aryl or the like) or OM (M is H, an aliphatic hydrocarbon or the like)], e.g. the one shown by formula II. It is preferable, in a light-emitting device having a light-emitting layer or two or more thin layers of organic compound(s) between a pair of electrodes, that at least one layer contains the compound shown by formula I, in particular dispersed in a polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for a light emitting device used for a flat light source or display and a light emitting device with high luminance. More specifically, the present invention relates to a light emitting material capable of emitting sharp light with high color purity from green to red with high luminance and high efficiency at a low applied voltage, and a light emitting element using the same.

[0002]

2. Description of the Related Art Light-emitting elements using organic substances are expected to be used as inexpensive large-area, full-color display elements of the solid-state light-emitting type, and many developments have been made. In general, a light emitting element includes a light emitting layer and a pair of opposed electrodes sandwiching the light emitting layer. Light emission occurs when an electric field is applied between both electrodes.
Electrons are injected from the cathode, and holes are injected from the anode.
Further, the electrons and holes are recombined in the light emitting layer, and the energy is emitted as light when the energy level returns from the conduction band to the valence band.

[0003] Conventional light-emitting elements have a high driving voltage and low light emission luminance and light emission efficiency. In addition, the characteristic deterioration was remarkable, and it had not been put to practical use. In recent years, a light emitting device in which a thin film containing an organic compound having high fluorescence quantum efficiency and emitting light at a low voltage of 10 V or less is laminated has been reported (Applied
Physics Letters, 51, 913, 1987
Years), has attracted interest. This method uses a metal chelate complex, a fluorescent band layer, and an amine compound for a hole injection layer,
High-luminance green light emission is obtained, and the luminance reaches several 1000 cd / m ² at a DC voltage of 6 to 7 V. However, in consideration of a practical device, development of a further higher luminance and higher efficiency light emitting device is desired. Further, in consideration of utilization as a full-color display and a light source, it is necessary to emit three primary colors or white in practical use. The above-described element uses an 8-quinolinol Al complex (Alq) as a light-emitting material, emits green light, and the development of light-emitting elements having other light-emitting colors is desired. Until now, various light emitting materials that emit light other than green light have been developed, but they have problems such as low light emission luminance, low light emission efficiency, and low durability, and have not been put to practical use.

Further, a conventional light-emitting device having high luminous efficiency is obtained by doping a light-emitting material such as a fluorescent dye in a charge transport material in a small amount, and it is difficult to obtain reproducibility of device characteristics in manufacturing. In addition, there are problems such as a decrease in luminance and a change in color when used for a long time due to low durability of the dye. As a means to solve this, the development of a material that has both a charge transport function and a light emitting function is desired, but in the materials developed so far, if a fluorescent dye is used as a charge transport material at a high concentration, concentration quenching etc. There are problems such as difficulty in emitting high-luminance light and deterioration of device characteristics due to aggregation over time.

On the other hand, organic light-emitting devices that achieve high-luminance light emission are devices in which organic substances are stacked by vacuum deposition. However, from the viewpoints of simplification of the manufacturing process, workability, and large area, etc. It is desirable to produce the element by a coating method.
However, a device manufactured by a conventional coating method is inferior to a device manufactured by a vapor deposition method in terms of luminous luminance and luminous efficiency, and high luminance and highly efficient luminescence have been major issues. Further, in a device in which an organic low-molecular compound is dispersed and applied in an organic polymer medium, there is a problem that it is difficult to emit uniform planar light due to aggregation of the organic low-molecular compound when light is emitted for a long time.

[0006]

SUMMARY OF THE INVENTION A first object of the present invention is to emit light with high luminance and high efficiency by driving at a low voltage, having excellent stability in repeated use, and capable of emitting uniform planar light. An object is to provide an element material and a light emitting element. A second object of the present invention is to provide a light emitting element material and a light emitting element which emit light with good color purity.

[0007]

This object has been achieved by the following means. (1) A light-emitting element material, which is a compound represented by the following general formula (I).

[0008]

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Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ ,
R ₆ , R ₇ , R ₈ and R ₁₁ each represent a hydrogen atom or a substituent. X represents O, S or NR (R represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group). Z is N—R _a R _b (R _a and R _b each represent a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group) or —OM (M is a hydrogen atom, an aliphatic hydrocarbon group, An aryl group, a heterocyclic group or a cation). )

(2) In a light-emitting element having a light-emitting layer or a plurality of organic compound thin layers including the light-emitting layer formed between a pair of electrodes, at least one of the light-emitting elements has the general formula (I) described in the above item (1).
A light-emitting element comprising a layer containing a compound represented by the formula: (3) In a light-emitting element in which a light-emitting layer or a plurality of organic compound thin layers including a light-emitting layer is formed between a pair of electrodes, at least one of the compounds represented by the general formula (I) described in the above item (1) is used as a polymer. A light-emitting element, which is a dispersed layer. A further preferred embodiment is the following means. (4) The light emitting device according to the above (2), wherein the light emitting layer contains a compound represented by the general formula (I). (5) In a light-emitting element in which a light-emitting layer or a plurality of organic compound thin layers including the light-emitting layer are formed between a pair of electrodes, at least one layer between the light-emitting layer and the cathode contains the light-emitting element material described in the above (1). A light-emitting element, which is a layer to be formed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION First, the compound represented by formula (I) of the present invention will be described in detail. R ₁ , R ₂ , R
₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₁₁ each represent a hydrogen atom or a substituent. R ₁ , R ₂ , R ₃ , R
_{As the} substituent represented by ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₁₁ , for example, an alkyl group (preferably having 1 to carbon atoms)
20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, for example, methyl, ethyl, iso-
Propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl and the like. ), An alkenyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 12 carbon atoms, particularly preferably having 2 to 8 carbon atoms, and examples thereof include vinyl, allyl, 2-butenyl, and 3-pentenyl. ), Alkynyl group (preferably having 2 to 2 carbon atoms)
20, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl and 3-pentynyl. ), An aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably having 6 to 12 carbon atoms, for example, phenyl, p-
Methylphenyl, naphthyl and the like can be mentioned. ), An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, and examples thereof include amino, methylamino, dimethylamino, diethylamino, and dibenzylamino. ), An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 12 carbon atoms, particularly preferably having 1 to 8 carbon atoms, and examples thereof include methoxy, ethoxy, and butoxy), and aryloxy. Group (preferably having 6 to 2 carbon atoms)
It has 0, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples include phenyloxy and 2-naphthyloxy. ), An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, acetyl,
Benzoyl, formyl, pivaloyl and the like can be mentioned. ), An alkoxycarbonyl group (preferably having 2 carbon atoms)
-20, more preferably 2-16 carbon atoms, particularly preferably 2-12 carbon atoms, for example, methoxycarbonyl,
Ethoxycarbonyl and the like. ), An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, and particularly preferably having 7 to 1 carbon atoms.
0, for example, phenyloxycarbonyl and the like. ), An acyloxy group (preferably having 2 to 2 carbon atoms)
It has 0, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 10 carbon atoms, and examples thereof include acetoxy and benzoyloxy. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 16 carbon atoms, particularly preferably having 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), and an alkoxycarbonylamino group. (Preferably having 2 to 20 carbon atoms,
More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino. ), An aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably having 7 carbon atoms)
To 16, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino. ), A sulfonylamino group (preferably having 1 to 2 carbon atoms)
0, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, methanesulfonylamino,
Benzenesulfonylamino and the like. ), A sulfamoyl group (preferably having 0 to 20, more preferably 0 to 16, and particularly preferably 0 to 12 carbon atoms, for example, sulfamoyl, methylsulfamoyl,
Dimethylsulfamoyl, phenylsulfamoyl and the like can be mentioned. ), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl). An alkylthio group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 1 carbon atoms)
6, particularly preferably 1 to 12 carbon atoms, for example, methylthio, ethylthio and the like. ), An arylthio group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably having 6 to 12 carbon atoms, such as phenylthio, etc.), and a sulfonyl group (preferably having 1 carbon atom). ~ 20, more preferably 1 carbon atom
To 16, particularly preferably 1 to 12 carbon atoms, such as mesyl and tosyl. ), A sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 carbon atom)
To 16, particularly preferably 1 to 12 carbon atoms, for example, methanesulfinyl, benzenesulfinyl and the like. ), Ureido group (preferably having 1 to 20 carbon atoms,
More preferably, it has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include ureide, methylureide, and phenylureide. ), A phosphoric amide group (preferably having 1 to 20 carbon atoms, more preferably 1 carbon atom
To 16, particularly preferably 1 to 12 carbon atoms, for example, diethylphosphoramide, phenylphosphoramide and the like. ), Hydroxy, mercapto, halogen (eg, fluorine, chlorine, bromine, iodine), cyano, sulfo, carboxyl, nitro, hydroxamic acid, sulfino, hydrazino,
An imino group, a heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, Furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl and the like, and a silyl group (preferably having 3 to 40 carbon atoms, more preferably having 3 to 30 carbon atoms, and particularly preferably having 3 carbon atoms) ~ 24,
For example, trimethylsilyl, triphenylsilyl and the like can be mentioned). These substituents may be further substituted. When there are two or more substituents, they may be the same or different. When possible, they may be connected to each other to form a ring.

The substituent is preferably an alkyl group, an alkenyl group, an aralkyl group, an aryl group, an amino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbonylamino group, a sulfonylamino group,
A sulfamoyl group, a carbamoyl group, a hydroxy group, a heterocyclic group or a substituent connected to form a condensed ring, more preferably an alkyl group, an alkenyl group, an aralkyl group, an aryl group, an amino group, a carbonylamino group, A sulfonylamino group, a heterocyclic group and a substituent are connected to form a benzene ring, more preferably an alkyl group, an aralkyl group, an aryl group, an amino group, a carbonylamino group, a sulfonylamino group, a hydroxy group,
A benzene ring is formed by linking a cyano group, a heterocyclic group, and a substituent.

R ₁ , R ₂ and R ₃ are preferably a hydrogen atom and an alkyl group, more preferably a hydrogen atom and a lower alkyl group, and particularly preferably a hydrogen atom.
R ₄ is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a lower alkyl group, and particularly preferably a hydrogen atom or a methyl group. R ₅ , R ₆ , R ₇ , R ₈
Preferably a hydrogen atom, an alkyl group, an aryl group,
Halogen atom, cyano group, sulfonyl group, heterocyclic group,
Substituents are linked to form a benzene ring, more preferably a hydrogen atom, a lower alkyl group (for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group,
a t-butyl group, a trifluoromethyl group and the like), an aryl group (for example, a phenyl group, a p-methylphenyl group, a naphthyl group and the like), a halogen atom,
There is a cyano group. More preferably, they are a hydrogen atom, a chlorine atom, and a cyano group. R ₁₁ is preferably a hydrogen atom,
An alkyl group, an aryl group, or a heterocyclic group, more preferably a hydrogen atom, a lower alkyl group, an aryl group, or an aromatic heterocyclic group; and still more preferably, a hydrogen atom, a methyl group, an ethyl group, or a carbon number of 6 to Twelve aryl groups, particularly preferably a hydrogen atom, a methyl group, and a phenyl group.

X is O, S or NR (R is a hydrogen atom,
Represents an aliphatic hydrocarbon group, an aryl group or a heterocyclic group. ). The aliphatic hydrocarbon group represented by R is a linear, branched or cyclic alkyl group (preferably having 1 carbon atom).
~ 30, more preferably 1 ~ 20, still more preferably 1 ~ 1
12, for example, methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n
-Hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl and the like. ), An alkenyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, still more preferably 2 to 12 carbon atoms, for example, vinyl, allyl,
2-butenyl, 3-pentenyl and the like. ),
An alkynyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, still more preferably 2 to 12 carbon atoms, such as propargyl and 3-pentynyl), preferably an alkyl group or an alkenyl group; And more preferably a methyl group, an ethyl group, a propyl group, a butyl group, and an allyl group.

The aryl group represented by R is preferably a monocyclic or bicyclic aryl group having 6 to 30 carbon atoms (for example, phenyl, naphthyl, etc.).
A phenyl group having 6 to 20 carbon atoms is more preferable, and a phenyl group having 6 to 12 carbon atoms is still more preferable.

The heterocyclic group represented by R is a 3- to 10-membered saturated or unsaturated heterocyclic ring containing at least one of N, O and S atoms, and these may be monocyclic. Or a condensed ring with another ring. The heterocyclic group is preferably an aromatic heterocyclic group, more preferably a 5-aromatic heterocyclic group containing a nitrogen atom, and even more preferably an aromatic heterocyclic group containing 1 or 2 nitrogen atoms. Specific examples of the heterocycle include, for example, pyrrolidine, piperidine, piperazine, morpholine, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiazole, thiadiazole, Oxazoline, oxazole, oxadiazole, quinoline,
Examples include isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, and tetrazaindene. Preferably as a heterocycle, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, thiadiazole, oxadiazole, quinoline,
Phthalazine, quinoxaline, quinazoline, cinnoline,
Tetrazole, thiazole, oxazole benzimidazole, benzoxazole, benzothiazole, benzotriazole, more preferably imidazole,
Pyridine, quinoline, thiazole, oxazole, benzimidazole, benzoxazole, benzothiazole and benzotriazole, more preferably pyridine and quinoline.

The aliphatic hydrocarbon group, aryl group and heterocyclic group represented by R may have a substituent, and the substituents described above as the substituents of R ₁ to R ₈ can be applied. R is preferably an alkyl group, an alkenyl group, or an aryl group, and more preferably an alkyl group or a phenyl group. X is preferably O, NR, and more preferably O.

Z is -NR_aR_bOr with -OM
R_aAnd R_bAre the same or different
And a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or
Represents a heterocyclic group. Note that R_aAnd R_bAre connected to form a ring
And R_a, R _bIs bonded to the benzene ring
To form a condensed ring. M is a hydrogen atom, aliphatic carbon
Shows hydrogen group, aryl group, heterocyclic group or cation
You.

The aliphatic hydrocarbon group represented by R _a or R _b is a linear, branched or cyclic alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, still more preferably 1 to 12 carbon atoms). And include, for example, methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), alkenyl group (preferably having 2 to 2 carbon atoms). 30, more preferably 2 to 2
0, more preferably 2 to 12, for example, vinyl, allyl, 2-butenyl, 3-pentenyl and the like. ), An alkynyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, still more preferably 2 to 12 carbon atoms, for example, propargyl, 3-pentynyl, etc.), preferably an alkyl group, an alkenyl group. And more preferably a group in which a methyl group, an ethyl group, a propyl group, a butyl group, an allyl group, R _a and R _b are bonded to a benzene ring to form a condensed ring (for example, a urolidine ring).

The aryl group represented by R _a and R _b is a monocyclic or bicyclic aryl group having 6 to 30 carbon atoms (for example, phenyl, naphthyl, etc.), and preferably has 6 to 20 carbon atoms. Phenyl group, more preferably 6 to 12
Is a phenyl group. If possible, _Ra and _Rb
May combine to form a ring, or _Ra and _Rb may combine with a benzene ring to form a condensed ring. .

The heterocyclic group represented by R _a or R _b is a 3- to 10-membered saturated or unsaturated hetero ring containing at least one of N, O and S atoms, and these are a single ring. It may be a ring, or may form a condensed ring with another ring. The heterocyclic group is preferably an aromatic heterocyclic group, and more preferably an aromatic heterocyclic group containing a nitrogen atom or a sulfur atom. Specific examples of the heterocycle include, for example, pyrrolidine, piperidine, piperazine,
Morpholine, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole,
Quinoline, isoquinoline, phthalazine, naphthyridine,
Quinoxaline, quinazoline, cinnoline, pteridine,
Acridine phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, tetrazaindene and the like. Preferred as the heterocycle are thiophene, triazole, oxazole, piperidine, triazine and quinoline, more preferably thiophene,
Piperidine, triazine and quinoline. More preferably, it is thiophene.

An aliphatic hydrocarbon group represented by R _a or R _b ,
The aryl group and the heterocyclic group may have a substituent, and as the substituent, those exemplified as the substituents for R ₁ to R ₈ can be applied.

R _a and R _b are preferably a hydrogen atom, an alkyl group (preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms (substituents include those mentioned as substituents of R ₁ to R ₈ ) And an aryl group and an aromatic heterocyclic group, more preferably an aryl group and an aromatic heterocyclic group, and still more preferably an aryl group (preferably a monocyclic or bicyclic C6 to C30 ring). An aryl group (for example, phenyl, naphthyl, etc.);
A phenyl group having 6 to 20 carbon atoms is more preferable, and a phenyl group having 6 to 12 carbon atoms is still more preferable. ).

The aliphatic hydrocarbon group represented by M is a straight-chain,
A branched or cyclic alkyl group (preferably having 1 to 3 carbon atoms)
0, more preferably 1 to 20, even more preferably 1 to 12
For example, methyl, ethyl, iso-propyl, t
tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl and the like. ), An alkenyl group (preferably having 2 to 30, more preferably 2 to 20, and still more preferably 2 to 12, and examples thereof include vinyl, allyl, 2-butenyl, and 3-pentenyl), and an alkynyl group. (Preferably has 2 to 30 carbon atoms, more preferably 2 carbon atoms.
To 20, more preferably 2 to 12, and examples include propargyl and 3-pentynyl. )
Preferred are an alkyl group and an alkenyl group, and more preferred are a methyl group, an ethyl group, a propyl group, a butyl group and an allyl group.

The aryl group represented by M has 6 to 3 carbon atoms.
0 is a monocyclic or bicyclic aryl group (eg, phenyl, naphthyl, etc.), preferably a phenyl group having 6 to 20 carbon atoms, more preferably a phenyl group having 6 to 12 carbon atoms.

The heterocyclic group represented by M is a 3- to 10-membered saturated or unsaturated heterocyclic ring containing at least one of N, O and S atoms, and these may be monocyclic. Or a condensed ring with another ring. The heterocyclic group is preferably an aromatic heterocyclic group, and more preferably an aromatic heterocyclic group containing a nitrogen atom or a sulfur atom. Specific examples of the heterocycle include, for example, pyrrolidine, piperidine, piperazine, morpholine, thiophene, furan, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole,
Triazine, indole, indazole, purine, thiazoline, thiazole, thiadiazole, oxazoline,
Oxazole, oxadiazole, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, tetrazaindene, and the like.
Preferred as the hetero ring are thiophene, triazole, oxazole, piperidine, triazine and quinoline, and more preferred are thiophene, piperidine, triazine and quinoline. More preferably, it is thiophene.

Examples of the cation represented by M include metal cations (eg, lithium cation, sodium cation, potassium cation, cesium cation, magnesium cation, calcium cation, aluminum cation, europium cation) and quaternary ammonium ion (preferably Has 1 to 30, more preferably 1 to 20, more preferably 1 to 10, carbon atoms, such as tetrabutylammonium ion. The metal cation may have a ligand.

The aliphatic hydrocarbon, aryl group, and heterocyclic group represented by M may have a substituent, and examples of the substituent include those described for R _{1 to} R _8. Is an alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20, more preferably 1 to 10, for example,
A methyl group, an ethyl group, an n-propyl group, an isopropyl group, a methoxyethoxymethyl, etc.), an aryl group (preferably having 6 to 30, more preferably 6 to 20, and still more preferably 6 to 10; Phenyl group, p
-Methoxyphenyl group), and more preferably an alkyl group. M is preferably a hydrogen atom, an alkyl group, an aryl group, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a zinc ion, a europium ion, or a quaternary ammonium ion, and more preferably a hydrogen atom, an alkyl group, or an aryl group. And more preferably a hydrogen atom or a methyl group. Preferably the Z is -NR _a R _b.

Among the compounds represented by the general formula (I), a compound represented by the general formula (Ia) is preferable.

[0030]

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Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ ,
R ₆ , R ₇ , R ₈ , R ₁₁ and X are each represented by the general formula (I)
And the preferred range is also the same. R ₂₁ and R ₂₂ represent an aryl group or a heterocyclic group. The aryl group is preferably a monocyclic or bicyclic aryl group having 6 to 30 carbon atoms, more preferably a phenyl group having 6 to 20 carbon atoms, and further preferably a phenyl group having 6 to 12 carbon atoms. The heterocyclic group is preferably an aromatic heterocyclic group. More preferably, R ₂₁ and R ₂₂ are
A monocyclic or bicyclic aryl group having 6 to 30 carbon atoms,
More preferably, it is a phenyl group having 6 to 20 carbon atoms, particularly preferably a phenyl group having 6 to 12 carbon atoms. )

Among the compounds represented by the general formula (I), more preferred are the compounds represented by the general formula (Ib).

[0033]

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(Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ ,
R ₆ , R ₇ , R ₈ , and R ₁₁ have the same meanings as those in formula (I), and the preferred ranges are also the same. Ar ₁ and Ar ₂ represent an aryl group or an aromatic heterocyclic group. The aryl group preferably has 6 to 30 carbon atoms.
A monocyclic or bicyclic aryl group, more preferably a phenyl group having 6 to 20 carbon atoms, still more preferably 6 to 12
Is a phenyl group. Ar ₁ and Ar ₂ are more preferably a monocyclic or bicyclic aryl group having 6 to 30 carbon atoms, further preferably a phenyl group having 6 to 20 carbon atoms, particularly preferably a phenyl group having 6 to 12 carbon atoms. is there. )

The compound represented by the general formula (I) may be a low molecular weight compound, or a high molecular weight compound having a residue in which a polymer main chain is connected (preferably a weight average molecular weight of 1000).
５5,000,000, more preferably 5,000 to 2,000
000, more preferably 10,000-100,000
0) or a high molecular weight compound having a main chain of the compound of the present invention (preferably a weight average molecular weight of 1,000 to 500,000)
0, more preferably 5,000 to 2,000,000, and still more preferably 10,000 to 1,000,000). In the case of a high molecular weight compound, it may be a homopolymer or a copolymer with another polymer. The compound used in the present invention is preferably a low molecular weight compound. Further, in the above general formula, the compound is represented by an extreme structure for convenience, but may be a tautomer thereof.

Specific examples of the compound represented by formula (I) are shown below, but the present invention is not limited thereto.

[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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The above compound examples may be tautomers thereof.

The light emitting device of the present invention is a device in which a light emitting layer or a plurality of organic compound thin layers including the light emitting layer is formed between a pair of anode and cathode electrodes. It may have a layer, an electron injection layer, an electron transport layer, a protective layer, and the like, and each of these layers may have another function. Various materials can be used for forming each layer.

The anode supplies holes to the hole injection layer, the hole transport layer, the light emitting layer, and the like. A metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof is used. It is possible to use a material having a work function of 4 eV or more. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, and indium tin oxide (ITO), or metals such as gold, silver, chromium, and nickel, and furthermore, these metals and conductive metal oxides. Mixtures or laminates, inorganic conductive substances such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO, and the like. Oxides,
In particular, ITO is preferable in terms of productivity, high conductivity, transparency, and the like. The thickness of the anode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, and still more preferably 100 nm to 500 nm.

As the anode, a layer formed on a soda lime glass, an alkali-free glass, a transparent resin substrate or the like is usually used. When glass is used, it is preferable to use non-alkali glass in order to reduce ions eluted from the glass. Further, when soda lime glass is used, it is preferable to use a glass coated with a barrier coat such as silica. The thickness of the substrate is not particularly limited as long as it is sufficient to maintain the mechanical strength. When glass is used, the thickness is usually 0.2 mm or more, preferably 0.7 mm or more. Various methods are used for producing the anode depending on the material. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating evaporation method, a chemical reaction method (such as a sol-gel method), and a coating of a dispersion of indium tin oxide are used. The film is formed by the method described above. The anode can be cleaned or otherwise treated to lower the device's drive voltage,
It is also possible to increase the luminous efficiency. For example, in the case of ITO, UV-ozone treatment or the like is effective.

The cathode supplies electrons to the electron injecting layer, the electron transporting layer, the light emitting layer and the like. Adhesion between the negative electrode and the adjacent layer such as the electron injecting layer, the electron transporting layer and the light emitting layer, the ionization potential, It is selected in consideration of stability and the like. As the material of the cathode, a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used, and specific examples thereof include an alkali metal (eg, Li, Na, K, etc.) or a fluoride thereof, and an alkaline earth metal. Metals such as Mg, Ca
Etc.) or its fluorides, gold, silver, lead, aluminum,
Sodium-potassium alloy or a mixed metal thereof, lithium-aluminum alloy or a mixed metal thereof, magnesium-silver alloy or a mixed metal thereof, indium, rare earth metals such as ytterbium, and the like, preferably having a work function of 4 eV or less. The material is more preferably aluminum, a lithium-aluminum alloy or a mixed metal thereof, a magnesium-silver alloy or a mixed metal thereof, or the like. The thickness of the cathode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, and still more preferably 100 nm to 1 μm. A method such as an electron beam method, a sputtering method, a resistance heating evaporation method, or a coating method is used for manufacturing the cathode, and a metal can be evaporated alone or two or more components can be simultaneously evaporated. Further, an alloy electrode can be formed by depositing a plurality of metals at the same time, or an alloy prepared in advance may be deposited. The sheet resistance of the anode and the cathode is preferably low, and is preferably several hundred Ω / □ or less.

The material of the light emitting layer is capable of injecting holes from an anode, a hole injection layer, or a hole transport layer and applying electrons from a cathode, an electron injection layer, or an electron transport layer when an electric field is applied. Any material can be used as long as it can form a layer having a function, a function of transferring injected charges, and a function of providing a field of recombination of holes and electrons to emit light. Preferably, the light-emitting layer contains the compound of the present invention, but other light-emitting materials of the compound of the present invention can also be used. For example, benzoxazole derivatives,
Benzimidazole derivatives, benzothiazole derivatives,
Styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxadiazole derivatives, aldazine derivatives, pyrazine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, Quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, cyclopentadiene derivatives, styrylamine derivatives, aromatic dimethylidin compounds, various metal complexes represented by metal complexes of 8-quinolinol derivatives and rare earth complexes, polythiophene, polyphenylene, polyphenylene And polymer compounds such as vinylene. Although the thickness of the light emitting layer is not particularly limited, it is usually 1n.
m to 5 μm, more preferably 5 to 5 μm.
nm to 1 μm, more preferably 10 nm to 500
nm. The method for forming the light-emitting layer is not particularly limited, but a method such as resistance heating evaporation, electron beam, sputtering, molecular lamination, coating (spin coating, casting, dip coating, etc.), and LB method And preferably a resistance heating evaporation and coating method.

The material of the hole injection layer and the hole transport layer has one of a function of injecting holes from the anode, a function of transporting holes, and a function of blocking electrons injected from the cathode. Anything should do. Specific examples thereof include carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styryl anthracene derivatives , Fluorenone derivative, hydrazone derivative, stilbene derivative, silazane derivative, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidin compound, porphyrin compound, polysilane compound,
Examples thereof include poly (N-vinylcarbazole) derivatives, aniline-based copolymers, thiophene oligomers, and conductive polymer oligomers such as polythiophene. The thicknesses of the hole injection layer and the hole transport layer are not particularly limited, but are usually preferably in the range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, and still more preferably 10 nm to 5 μm.
00 nm. The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. Examples of the method for forming the hole injection layer and the hole transport layer include a vacuum deposition method, an LB method, and a method in which the hole injection / transport agent is dissolved or dispersed in a solvent and coated (spin coating method, casting method, dip coating method). Etc.) are used. In the case of the coating method, it can be dissolved or dispersed together with the resin component. Examples of the resin component include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, and poly (N -Vinyl carbazole), hydrocarbon resins, ketone resins, phenoxy resins, polyamides, ethyl cellulose, vinyl acetate, ABS resins, polyurethanes, melamine resins, unsaturated polyester resins, alkyd resins, epoxy resins, silicone resins, and the like.

The material of the electron injecting layer and the electron transporting layer is not limited as long as it has a function of injecting electrons from the cathode, a function of transporting electrons, or a function of blocking holes injected from the anode. Good. Specific examples thereof include triazole derivatives, oxazole derivatives, oxadiazole derivatives,
Heterocyclic tetracarboxylic anhydrides such as fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthalene perylene, and phthalocyanine derivatives And various metal complexes typified by metal complexes of 8-quinolinol derivatives, metal phthalocyanines, and metal complexes having benzoxazole or benzothiazole as ligands. The thickness of the electron injection layer and the electron transport layer is not particularly limited, but is usually 1 nm to 5 μm.
m, more preferably 5 nm to 1
μm, and more preferably 10 nm to 500 nm. The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-mentioned materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. Examples of the method for forming the electron injection layer and the electron transport layer include a vacuum deposition method, an LB method, and a method in which the electron injection and transport agent is dissolved or dispersed in a solvent and coated (spin coating, casting, dip coating, and the like). Is used. In the case of the coating method, it can be dissolved or dispersed together with the resin component. As the resin component, for example, those exemplified in the case of the hole injection transport layer can be applied.

As the material of the protective layer, any material may be used as long as it has a function of preventing a substance which promotes element deterioration such as moisture and oxygen from entering the element. As a specific example,
In, Sn, Pb, Au, Cu, Ag, Al, Ti, N
metal such as i, MgO, SiO, SiO ₂ , Al ₂ O ₃ ,
GeO, NiO, CaO, BaO, Fe 2 O 3, Y 2 O 3
, TiO _{2 and} other metal oxides, MgF ₂ , LiF, Al
F ₃ , metal fluoride such as CaF ₂ , polyethylene, polypropylene, polymethyl methacrylate, polyimide,
Polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, copolymerizing a monomer mixture containing tetrafluoroethylene and at least one comonomer Copolymer obtained, a fluorine-containing copolymer having a cyclic structure in the copolymer main chain, a water-absorbing substance having a water absorption of 1% or more,
A moisture-proof substance having a water absorption of 0.1% or less can be used. There is no particular limitation on the method for forming the protective layer. For example, a vacuum deposition method, a sputtering method, a reactive sputtering method,
BE (molecular beam epitaxy) method, cluster ion beam method, ion plating method, plasma polymerization method (high frequency excitation ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating Law can be applied.

[0054]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Example 1 Light-Emitting Element Fabrication Evaluation IT was placed on a 25 mm × 25 mm × 0.7 mm glass substrate.
A film formed of O with a thickness of 150 nm (manufactured by Tokyo Sanyo Vacuum Co., Ltd.) was used as a transparent support substrate. After etching and washing this transparent support substrate, poly (N-vinylcarbazole)
40 mg, PBD (2- (4-biphenylyl) -5-
(4-tert-butylphenyl) -1,3,4-oxadiazole) 12 mg, the compound described in Table 1 0.5 mg
Was dissolved in 3 ml of 1,2-dichloroethane and washed I
It was spin-coated on a TO substrate. The thickness of the resulting organic thin layer was about 120 nm. A mask (a mask having a light-emitting area of 5 mm × 5 mm) patterned on the organic thin layer is installed, and magnesium: silver = 10:
1 was co-evaporated to 50 nm, and then 50 nm of silver was evaporated to prepare a light-emitting element. Using a source measure unit 2400 manufactured by Toyo Technica, a DC constant voltage is applied to the light-emitting element to emit light, and the luminance is measured by a luminance meter BM-8 manufactured by Topcon, and a spectrum analyzer manufactured by Hamamatsu Photonics uses a luminous wavelength and CIE chromaticity coordinates. It was measured using PMA-11. After leaving the fabricated device at 60 ° C. and 20% RH for 3 hours (drive voltage: 15 V), the presence or absence of a dark spot on the light emitting surface was evaluated. Table 1 shows the results.

[0055]

Embedded image

As is clear from the results in Table 1, in the device using the compound of the present invention, the known comparative compounds A and B were compared with the comparative compound C described in Japanese Patent Application Laid-Open (JP-A-6-228544). In addition, it exhibited excellent performance in terms of uniform planar light emission and durability, such as low voltage driving, high luminance light emission, and little occurrence of dark spots over time.
In particular, good light-emitting characteristics were obtained by a coating method with low light emission luminance.

[0057]

[Table 1]

Example 2 After etching and cleaning the ITO substrate in the same manner as in Example 1,
PD (N, N-bis (3-methylphenyl) -N, N-
Diphenylbenzidine) about 40 nm, the compounds described in Table 2 about 20 nm, 2,5-bis (1-naphthyl) -1,3,3.
About 40 nm of 4-oxadiazole in order of 10 ^-5 to 10 ^-6
Vapor deposition was performed at a substrate temperature of room temperature in a vacuum of Torr.
Next, a cathode was vapor-deposited in the same manner as in Example 1 to produce a light-emitting device, which was evaluated. Table 2 shows the results. As is evident from the results in Table 2, the device using the compound of the present invention showed less occurrence of dark spots over time, and emitted light with higher luminance even in the vapor deposition method than the comparative compound.

[0059]

[Table 2]

Embodiment 3 After etching and cleaning the ITO substrate in the same manner as in Embodiment 1,
After vapor deposition of about 40 nm of PD, the compounds shown in Table 3 and A
1q (tris (8-hydroxyquinolinato) aluminum) was co-deposited at a deposition rate of 0.04 ° / sec and 4 ° / sec to a film thickness of about 60 nm. Next, Example 1
A light emitting device was prepared by evaporating a cathode in the same manner as described above, and was evaluated. Table 3 shows the results. As is evident from the results in Table 3, the device using the compound of the present invention exhibited better color purity and higher luminance emission than the comparative compound even in the vapor-doped system.

[0061]

[Table 3]

Example 4 After etching and cleaning the ITO substrate in the same manner as in Example 1,
After depositing PD with a thickness of about 40 nm, Exemplified Compound 6 was deposited with a thickness of about 40 nm.
Then, Alq (tris (8-hydroxyquinolinato) aluminum) was deposited at a deposition rate of 0.04 °.
/ Sec, 4Å / sec. Next, a cathode was vapor-deposited in the same manner as in Example 1 to produce a light-emitting element, and as a result of evaluation, it was found that λmax = 640 nm showing 7200 cd / cm ² at the lowest driving voltage, 6 V, and the highest luminance of 18 V, C
IE chromaticity (x, y) = (0.69, 0.29), no generation of dark spots was observed. As is apparent from these results, the device using the compound of the present invention exhibited high-luminance emission even in the non-doped system of the vapor deposition method.

Example 5 After etching and washing the ITO substrate in the same manner as in Example 1, about 60 nm of Exemplified Compound 6 was deposited, and then Alq (tris (8-hydroxyquinolinato) aluminum) was deposited to a thickness of about 40 nm. . Then depositing the cathode in the same manner as in Example 1 to form a light-emitting element, as a result of the evaluation, minimum driving voltage, 5V, maximum brightness 18V at 400 cd / cm ^2,
.lambda.max = 640 nm. As is clear from these results, it was found that the compound of the present invention was also effective as a hole injecting / transporting and luminescent agent, and exhibited high-luminance emission. .

[0064]

According to the present invention, it is possible to obtain a light emitting device having good color purity, low voltage driving, high luminance and long life as compared with the prior art. In particular, good light-emitting characteristics can be obtained even in a coating method with low light emission luminance, and an element can be produced which is advantageous in terms of manufacturing cost and the like.

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Claims (3)

[Claims] 1. A compound represented by the following general formula (I):
A light-emitting element material, characterized in that: General formula (I)(Where R₁ , R_Two , R_Three , R_Four , R_Five , R₆ , R₇ ,
R₈ And R₁₁Represents a hydrogen atom or a substituent, respectively.
You. X is O, S or NR (R is a hydrogen atom, an aliphatic carbon
Represents a hydride group, an aryl group or a heterocyclic group. )
You. Z is NR_aR _b(R_a, R_bAre hydrogen sources
, An aliphatic hydrocarbon group, an aryl group or a heterocyclic group
Represent. ) Or -OM (M is a hydrogen atom, aliphatic hydrocarbon
Group, aryl group, heterocyclic group or cation
You. ). 2. A light-emitting element in which a light-emitting layer or a plurality of organic compound thin layers including the light-emitting layer is formed between a pair of electrodes,
At least one layer is a layer containing the compound represented by the general formula (I) according to claim 1. 3. A light-emitting element in which a light-emitting layer or a plurality of organic compound thin layers including a light-emitting layer is formed between a pair of electrodes,
A light-emitting device comprising at least one layer in which a compound represented by the formula (I) according to claim 1 is dispersed in a polymer.